RuO2 thin films were deposited on SiO2/Si substrate at low temperatures by hot-wall metallorganic chemical vapor deposition using the ruthenocene and oxygen gas mixtures. The preferred orientation of films varied from (200) to (101) as the film thickness increases above 150 nm irrespective of the deposition conditions. RuO2 deposition reaction was controlled by gas-phase mass-transfer in these experiments. The film resistivity increased with increasing oxygen flow rates. The increase of film resistivity with increasing oxygen flow rates was due to the contribution of carrier concentration rather than that of carrier mobility. The film resistivity with increasing the annealing temperatures decreased because of densification of films.